1. Field of the Invention
The present invention relates to a plasma processing method and post-processing method, and more specifically to a plasma processing method and post-processing method for performing an etching process or the like on, e.g., a semiconductor wafer.
2. Description of the Related Art
Where a dry etching process using a corrosive gas, such as hydrogen bromide or chlorine, is performed on a substrate, such as a semiconductor wafer, it is necessary to take countermeasures against particle generation due to peel-off of reaction products deposited inside the process chamber, and deterioration of the process chamber due to the corrosive gas. Accordingly, it has been proposed to perform cleaning with O2 plasma after dry etching in the Japanese Patent Publication (KOKAI) No. 63-5532. This O2 plasma cleaning has the effects of replacing a halogen atmosphere within the chamber and preventing the chamber from being corroded, and may further have the effect of sputtering and removing a corrosive gas adsorbed on the substrate.
However, deposits of reaction products are present on the substrate after the etching process, and, for example, in the case of etching of a silicon substrate, deposits of reaction products comprise, e.g., SiBr4 or SiCl4. Such deposits cannot be completely removed by the cleaning process with O2 plasma.
As described above, deposits on a substrate cannot be completely removed by the cleaning process with O2 plasma. The deposits described above remaining on the substrate are predisposed to generate a corrosive gas, such as a halogen gas, when placed at a position open to atmosphere pressure. Accordingly, when the substrate is transferred to a subsequent process by a transfer system, a corrosive gas may be generated from the deposits on the substrate and corrode the transfer system. In general, as regards chambers for performing a process of e.g., etching using a corrosive gas, the inner surface thereof is made of aluminum or alumite, which can be a preliminary corrosion countermeasure. However, transfer systems are not designed to be in contact with a corrosive gas, and thus can be easily corroded. If transfer systems are deteriorated due to corrosion, particle contamination may be caused, and the systems may significantly reduce the durability as a whole. However, so far, corrosion countermeasures have been barely studied for transfer systems.